The German authorities are now verifying statements of thousands of Afghan refugees, who came to Germany and claimed to be former Taliban militants, the German Der Spiegel weekly reports, adding that criminal investigations have been launched in 70 cases.

Since 2015, several thousands of refugees who came from Afghanistan admitted during interviews with representatives of the German Federal Office for Migration and Refugees (BAMF) that they either had contacts with some radical Islamist groups in Afghanistan or directly fought for the extremists, Der Spiegel reports, citing data provided by the BAMF to the German security services.

The weekly also says that the German Federal Prosecutor’s Office has already opened criminal cases against 70 Afghan refugees after verifying their statements. Six asylum seekers have been already arrested, the media reports, adding that legal action against some of the suspects will be initiated next week.

However, it is still unclear if all refugees who declared themselves Taliban fighters indeed fought for the extremists or had links to any radical group. According to Der Spiegel, the German authorities suspect that some asylum seekers may be seeking to boost their prospects of receiving asylum in Germany in this way, as affiliation with the Taliban is punishable with the death penalty in Afghanistan.

In November 2016, it was reported that the German authorities planned to send home some 12,000 Afghans as they considered the security situation in Afghanistan safe enough. Under such circumstances, the refugees might try to indicate that it is not safe for them to be sent back because they would face imminent death at the hands of the authorities.

However, German security services expect a surge in anti-terrorist investigations against alleged Taliban fighters in addition to the inquiries, which were already launched against the members of Islamic State (IS, former ISIS/ISIL) terrorist group in Germany.

The German Federal Prosecutor’s Office warns that it is already “pushed to the limit” by the sheer number of anti-terrorist investigations it has to pursue. In 2016, the agency opened 200 criminal cases against suspected Islamic terrorists, Germany’s Die Welt daily reports.

In early March, the head of Germany’s domestic intelligence agency (BfV), Hans-Georg Maassen, said that Islamists could carry out terrorist attacks at any time, warning that “the potential of violence-oriented Islamists in Germany is growing steadily and will continue to increase.”

He also said that his agency has as many as 1,600 people on its radar.

In the meantime, one Taliban leader tried to claim asylum in Germany using fake ID papers. Abdul Rauf Mohammed, the former health minister under the Taliban between 1996 and 2001, arrived at Germany’s Frankfurt airport from the Saudi Arabian capital, Riyadh, presented a fake passport and applied for asylum for himself and his family members.

However, the German authorities promptly uncovered his true identity and rejected his asylum request, sending him back to Saudi Arabia.

US-led forces, including Germany, invaded Afghanistan to oust the Taliban from power more than 15 years ago, following the attacks of September 11, 2001. However, the extremist group, which advocates strict Islamist rule, is still active and continues to attack Afghan military and carry out terrorist attacks.

On Friday, more than 100 Afghan soldiers were killed and injured in a Taliban attack on a military base in northern Afghanistan, according to the Afghan Defense Ministry.